[RT-AC68U] - Only two spatial streams when paired with Western Digital 1300 Bridge?
Hello-
Great community you have here! I’ve learned a ton from reading these pages.
I've searched through the forums and couldn't find a lot of discussions regarding the Western Digital My Net AC (1300) Bridge, so I thought I'd post my question here.
Update tl:dr version - Does anyone know if the WD 1300 Bridge is incapable of real-world throughput using all three spatial streams? I see on review sites that two routers (one as AP and one as bridge) can achieve over 550 Mbps, but I seem to be capped at around 433 Mbps with the WD bridge. Is the speed that resembles only two spatial stream operation just coincidence due to the limitations of the "cheaper" WD bridge?
Full version below
I was curious if anyone else has a similar setup--an RT-AC68U as the AP and the WD Bridge connected to the 5 GHz band with an 80 MHz channel bandwidth. If so, what kind of max throughput do you see when signal strength is taken out of the equation? And if not, I was curious if anyone could walk me through why it appears that I’m only getting the bridge to operate on 2 of the 3 potential spatial streams?
Here is some info on the bridge. It seems like it should be able to handle 3 spatial streams.
Wikidevi page
https://wikidevi.com/wiki/Western_Digital_My_Net_AC_Bridge
The router and the bridge are both “ac 1300” products and have 3x3:3 functionality. I understand that the max throughput is approximately half of the rated link rate due to the half-duplex nature of wifi, or approximately 650 Mbps (theoretical).
For testing, I’ve connected the bridge and router wirelessly as stated above and placed them in the same room with clear line of sight. A desktop with an SSD is hard-wired to the router with cat6, and a laptop with an SSD is connected to the bridge (and the ac7260 wifi adapter in the laptop is turned off physically and in Windows). When set up this way, I’ll achieve transfer rates (as shown in Windows) that start at ~80 MBps which is about the max of 650 Mbps. This higher reported speed is displayed for a second or two, but then the value drops to around 54 MBps for the entirety of the transfer. The lower rate is observed when double checked with a stopwatch. A speed of 54 MBps would translate to 433 Mbps, or equate to the real-world throughput of 802.11ac when only operating with 2 spatial streams (50% of 867 Mbps link rate). For what it’s worth, that speed is the same as what I can achieve when I use the 2x2:2 ac7260 adapter in the laptop and signal strength isn’t a factor. Interestingly, when the bridge is set up where it typically resides (~40ft away, diagonally through the house, a ceiling, a few walls, pipe stack) I’ll see the same phenomenon just with different speeds that seem to be scaled to the loss in signal strength. Namely, I’ll see around 58 MBps for a couple of seconds and then it will drop to about 30 MBps. This is still way better than what I see with the 7260, though (around 10-12 MBps).
And just to rule out any other equipment bottlenecks, when the laptop is also hard-wired to the router I can achieve 110-120 MBps transfers, so I’m essentially able to max out the 1000Mbps ports of the desktop and laptop.
In this article, the author seems to experience the same issue with the Western Digital bridge. Granted, he makes the mistake of saying he was hoping for 800-900 Mbps of throughput, which is an impossible link rate of 1600-1800 Mbps with a “1300” product. However, it doesn’t change that his numbers reflect a very similar situation to my own—a higher rate combined with an average rate that reflects operation on only two of the three spatial streams.
http://www.anandtech.com/show/7127/the-joys-of-80211ac-wifi/2
Also, I’ve read that even with two high-end ASUS ac1300 routers (configured as AP and bridge) the best speed achieved is around 550 Mbps. So it appears that even 50% throughput of the rated speed is wishful thinking with current ac1300 equipment.
dark slayer’s post on this page:
http://forums.smallnetbuilder.com/showthread.php?t=13649&highlight=rt-ac68u+bridge+mode&page=4
reference of the max 550 Mbps claim = geops’ second post on this page:
http://forums.smallnetbuilder.com/showthread.php?t=13649&highlight=rt-ac68u+bridge+mode&page=3
One other reference of achieving around 525 Mbps when benchmarking two 3x3:3 ac devices (one asus rt-ac66u as the AP, and another configured as a bridge)
http://www.pcworld.com/article/262149/asus_rt_ac66u_the_best_802_11ac_router_on_the_market_so_far.html
Ultimately, I’m hoping some of the experts in this forum can point me to something obvious I am missing, or point me to something more technical in the limitations of the bridge. Am I actually operating at 3 streams, but due to intrinsic limitations of wifi or the cheaper bridge, it’s just coincidence that the bridge seems like it’s only using two spatial streams? I’m savvy when it comes to PC hardware, but I am still educating myself when it comes to wifi/networking. With Black November happening, I’m curious if I should be looking into purchasing a second rt-ac68U to operate in bridge mode if the WD bridge is essentially misbranded and incapable of ever achieving over 433 Mbps of throughput. Or is that approach not worth it, since it seems like the best speed people see out of two ASUS ac1300 routers configured as AP and bridge is around 550 Mbps (so not a lot more than what I currently see)? Or, is the rt-ac68u to blame instead of the bridge, since the ac68u “appears” to have reduced dark slayer’s max speed to 433 Mbps (2 spatial streams) compared to the 525 Mbps (3 spatial streams) that they saw with the ac66u?
Am I getting hung up in numbers that don’t mean what I think they mean?
Thanks for your help!!
Apologies for the huge post.
Hello-
Great community you have here! I’ve learned a ton from reading these pages.
I've searched through the forums and couldn't find a lot of discussions regarding the Western Digital My Net AC (1300) Bridge, so I thought I'd post my question here.
Update tl:dr version - Does anyone know if the WD 1300 Bridge is incapable of real-world throughput using all three spatial streams? I see on review sites that two routers (one as AP and one as bridge) can achieve over 550 Mbps, but I seem to be capped at around 433 Mbps with the WD bridge. Is the speed that resembles only two spatial stream operation just coincidence due to the limitations of the "cheaper" WD bridge?
Full version below
I was curious if anyone else has a similar setup--an RT-AC68U as the AP and the WD Bridge connected to the 5 GHz band with an 80 MHz channel bandwidth. If so, what kind of max throughput do you see when signal strength is taken out of the equation? And if not, I was curious if anyone could walk me through why it appears that I’m only getting the bridge to operate on 2 of the 3 potential spatial streams?
Here is some info on the bridge. It seems like it should be able to handle 3 spatial streams.
Wikidevi page
https://wikidevi.com/wiki/Western_Digital_My_Net_AC_Bridge
The router and the bridge are both “ac 1300” products and have 3x3:3 functionality. I understand that the max throughput is approximately half of the rated link rate due to the half-duplex nature of wifi, or approximately 650 Mbps (theoretical).
For testing, I’ve connected the bridge and router wirelessly as stated above and placed them in the same room with clear line of sight. A desktop with an SSD is hard-wired to the router with cat6, and a laptop with an SSD is connected to the bridge (and the ac7260 wifi adapter in the laptop is turned off physically and in Windows). When set up this way, I’ll achieve transfer rates (as shown in Windows) that start at ~80 MBps which is about the max of 650 Mbps. This higher reported speed is displayed for a second or two, but then the value drops to around 54 MBps for the entirety of the transfer. The lower rate is observed when double checked with a stopwatch. A speed of 54 MBps would translate to 433 Mbps, or equate to the real-world throughput of 802.11ac when only operating with 2 spatial streams (50% of 867 Mbps link rate). For what it’s worth, that speed is the same as what I can achieve when I use the 2x2:2 ac7260 adapter in the laptop and signal strength isn’t a factor. Interestingly, when the bridge is set up where it typically resides (~40ft away, diagonally through the house, a ceiling, a few walls, pipe stack) I’ll see the same phenomenon just with different speeds that seem to be scaled to the loss in signal strength. Namely, I’ll see around 58 MBps for a couple of seconds and then it will drop to about 30 MBps. This is still way better than what I see with the 7260, though (around 10-12 MBps).
And just to rule out any other equipment bottlenecks, when the laptop is also hard-wired to the router I can achieve 110-120 MBps transfers, so I’m essentially able to max out the 1000Mbps ports of the desktop and laptop.
In this article, the author seems to experience the same issue with the Western Digital bridge. Granted, he makes the mistake of saying he was hoping for 800-900 Mbps of throughput, which is an impossible link rate of 1600-1800 Mbps with a “1300” product. However, it doesn’t change that his numbers reflect a very similar situation to my own—a higher rate combined with an average rate that reflects operation on only two of the three spatial streams.
http://www.anandtech.com/show/7127/the-joys-of-80211ac-wifi/2
Also, I’ve read that even with two high-end ASUS ac1300 routers (configured as AP and bridge) the best speed achieved is around 550 Mbps. So it appears that even 50% throughput of the rated speed is wishful thinking with current ac1300 equipment.
dark slayer’s post on this page:
http://forums.smallnetbuilder.com/showthread.php?t=13649&highlight=rt-ac68u+bridge+mode&page=4
reference of the max 550 Mbps claim = geops’ second post on this page:
http://forums.smallnetbuilder.com/showthread.php?t=13649&highlight=rt-ac68u+bridge+mode&page=3
One other reference of achieving around 525 Mbps when benchmarking two 3x3:3 ac devices (one asus rt-ac66u as the AP, and another configured as a bridge)
http://www.pcworld.com/article/262149/asus_rt_ac66u_the_best_802_11ac_router_on_the_market_so_far.html
Ultimately, I’m hoping some of the experts in this forum can point me to something obvious I am missing, or point me to something more technical in the limitations of the bridge. Am I actually operating at 3 streams, but due to intrinsic limitations of wifi or the cheaper bridge, it’s just coincidence that the bridge seems like it’s only using two spatial streams? I’m savvy when it comes to PC hardware, but I am still educating myself when it comes to wifi/networking. With Black November happening, I’m curious if I should be looking into purchasing a second rt-ac68U to operate in bridge mode if the WD bridge is essentially misbranded and incapable of ever achieving over 433 Mbps of throughput. Or is that approach not worth it, since it seems like the best speed people see out of two ASUS ac1300 routers configured as AP and bridge is around 550 Mbps (so not a lot more than what I currently see)? Or, is the rt-ac68u to blame instead of the bridge, since the ac68u “appears” to have reduced dark slayer’s max speed to 433 Mbps (2 spatial streams) compared to the 525 Mbps (3 spatial streams) that they saw with the ac66u?
Am I getting hung up in numbers that don’t mean what I think they mean?
Thanks for your help!!
Apologies for the huge post.
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